A so-called external drum image recording system having a drum wound with an imaging material such as a printing plate and a recording head comprising emission means emitting light in response to image data and moving along the axial direction of the drum is well known. This system rotates the drum at a high speed and moves the recording head along the axial direction of the drum for making the emission means emit light, thereby forming a two-dimensional image on the imaging material.
While the scanning rate can be improved in such an external drum image recording system by improving the rotational speed of the drum or increasing the number of arrays of the emission means mounted on the recording system, effectiveness thereof is limited.
In order to solve the aforementioned problem, a plurality of recording heads for recording images may conceivably be provided for parallelly scanning a plurality of areas on the printing plate and increasing speed. For example, an image recording system disclosed in Japanese Patent Application Laid-Open No. 9-185196 (1997) is formed with a plurality of recording heads arranged in a subscanning direction for parallelly recording images with the recording heads.